"for all packages, from release of 6.3 up to and including 6.4, we shipped
108 advisories to address 311 vulnerabilities. 18 advisories were rated
critical, 28 were important, and the remaining 62 were moderate and low."

"Updates to correct 77 of the 78 critical vulnerabilities were available via
Red Hat Network either the same day or the next calendar day after the
issues were public. The other one was in OpenJDK 1.60
where the update took 4 calendar days (over a weekend)."

And if you are interested in how the figures were calculated, here is the
working out:

Note that we can't just use a date range because we've pushed some
RHSA the weeks before 6.4 that were not included in the 6.4 spin.
These issues will get included when we do the 6.4 to 6.5 report (as
anyone installing 6.4 will have got them when they first updated).

Note: although we have 3 default criticals, they are in openjdk-1.6.0, but we
only call Java issues critical if they can be exploited via a browser, and in
RHEL6 the Java browser plugin is in the icedtea-web package, which isn't a
default package. So that means on a default install you don't get Java plugins
running in your browser, so really these are not default criticals in RHEL6
default at all.

"for all packages, from release of 6.2 up to and including 6.3, we shipped
88 advisories to address 233 vulnerabilities. 15 advisories were rated critical,
23 were important, and the remaining 50 were moderate and low."

"Updates to correct 34 of the 36 critical vulnerabilities were
available via Red Hat Network either the same day or the next calendar
day after the issues were public. The Kerberos telnet flaw was fixed
in 2 calendar days as the issue was published on Christmas day. The
second PHP flaw took 4 calendar days (over a weekend) as the initial
fix released upstream was incomplete."

And if you are interested in how
the figures were calculated, as always view the source of this
blog entry.

The Common Vulnerability Reporting Framework (CVRF) is a way to share
information about security updates in an XML machine-readable format. CVRF
1.1 got released this week and over at Red Hat we've started publishing
our security advisories in CVRF format.

Red Hat Enterprise Linux 5.8 was released today (February 2012), seven
months since the release of 5.7 in July 2011. So let's use this opportunity to
take a quick look back over the vulnerabilities and security updates made in
that time, specifically for Red Hat Enterprise Linux 5 Server.

Errata count

The chart below illustrates the total number of security updates issued for Red
Hat Enterprise Linux 5 Server if you had installed 5.7, up to and including the
5.8 release, broken down by severity. It's split into two columns, one for
the packages you'd get if you did a default install, and the other if you
installed every single package (which is unlikely as it would involve quite a bit of
manual effort to select every one). For a given installation, the number of
package updates and vulnerabilities that affected you will depend on exactly
what packages you have installed or removed.

So, for a default install, from release of 5.7 up to and including
5.8, we shipped 42 advisories to address 118 vulnerabilities. 4
advisories were
rated critical, 13 were important, and the remaining
25 were moderate and low.

Or, for all packages, from release of 5.7 up to and including 5.8, we
shipped 71 advisories to address 177 vulnerabilities. 7 advisories
were rated critical, 16 were important, and the remaining 48 were
moderate and low.

An update to the
MIT krb5 telnet daemon
(December 2011) where
a remote attacker who can access the telnet port of a target machine could use
this flaw to execute arbitrary code as root. Note that the krb5 telnet daemon
is not installed or enabled by default, and the default firewall rules block remote access to
the telnet port. This flaw did not affect the more commonly used telnet daemon distributed in the
telnet-server package.

Updates to
PHP
and
PHP 5.3
(February 2012)
where a remote attacker could send a specially-crafted HTTP request to cause the
PHP interpreter to crash or, possibly, execute arbitrary code. This flaw was
caused by the fix for CVE-2011-4885.

Updates to correct 19 out of the 20 critical vulnerabilities were
available via Red Hat Network either the same day or the next
calendar day after the issues were public. The update to krb5
took 2 calendar days because it was public on Christmas day.

Overall, for Red Hat Enterprise Linux 5 since release until 5.8, 98%
of critical vulnerabilities have had an update available to address
them available from the Red Hat Network either the same day or the
next calendar day after the issue was public.

Other significant vulnerabilities

Although not in the definition of critical severity, also of interest during
this period were a couple of remote denial of service flaws that were easily exploitable:

Previous update releases

To compare these statistics with previous update releases we need
to take into account that the time between each update release is different.
So looking at a default installation and calculating the number of
advisories per month gives the following chart:

This data is interesting to get a feel for the risk of running Enterprise
Linux 5 Server, but isn't really useful for comparisons with other major
versions, distributions, or operating systems -- for example, a default install
of Red Hat Enterprise Linux 4AS did not include Firefox, but 5 Server does. You
can use our public
security measurement data and tools, and run your own custom metrics for any
given Red Hat product, package set, timescales, and severity range of interest.

Red Hat Enterprise Linux 6.2 was released this week (Dec 2011), just
over six months since the release of 6.1 in May 2011. So let's
use this opportunity to take a quick look back over the
vulnerabilities and security updates made in that time, specifically
for Red Hat Enterprise Linux 6 Server.

Errata count

The chart below illustrates the total number of security updates issued for Red
Hat Enterprise Linux 6 Server if you had installed 6.1, up to and including the
6.2 release, broken down by severity. It's split into two columns, one for
the packages you'd get if you did a default install, and the other if you
installed every single package (which is unlikely as it would involve a bit of
manual effort to select every one). For a given installation, the number of
package updates and vulnerabilities that affected you will depend on exactly what you
have installed or removed.

So, for a default install, from release of 6.1 up to and including 6.2, we
shipped 36 advisories to address 121 vulnerabilities. 2 advisories were rated
critical, 10 were important, and the remaining 24 were moderate and low.

Or, for all packages, from release of 6.1 up to and including 6.2, we shipped
88 advisories to address 218 vulnerabilities. 10 advisories were rated critical,
16 were important, and the remaining 62 were moderate and low.

Updates to correct all of the 31 critical vulnerabilities were
available via Red Hat Network either the same day or the next calendar
day after the issues were public.

Other significant vulnerabilities

Although not in the definition of critical severity, also of interest during
this period were a few flaws that were high risk or easily exploitable:

A flaw in Bind, CVE-2011-4313
fixed by RHSA-2011:1458
where a malicious client could cause Bind to stop responding, a denial
of service attack. This flaw was discovered by it being accidentally
triggered in the wild.

A flaw in the Apache HTTP Server, CVE-2011-3192,
fixed by RHSA-2011:1245, where a remote attacker could
cause a denial of service attack. This was discovered due to a public exploit.

A flaw in RPM, CVE-2011-3378
fixed by RHSA-2011:1349
where a specially-crafted RPM package that, when queried or installed,
would cause rpm to crash or, potentially, execute arbitrary code prior to any
signature checking. We're not aware of any working exploits for this issue.

Previous update releases

To compare these statistics with previous update releases we need to take into
account that the time between each update release is different. So looking at
a default installation and calculating the number of advisories per month
gives the following chart:

This data is interesting to get a feel for the risk of running Enterprise
Linux 6 Server, but isn't really useful for comparisons with other major
versions, distributions, or operating systems -- for example, a default install
of either Red Hat Enterprise Linux 4AS and 6 Server does not include Firefox, but a
default install of 5 Server does. You can use
our public security
measurement data and tools, and run your own custom metrics for any given
Red Hat product, package set, timescales, and severity range of interest.

We pushed an
update to Flash Player for Red Hat Enterprise Linux Supplementary today, on
a Friday, because it fixed Critical vulnerabilities. But we try not to push
updates on a Friday unless they are critical and already public.

So let's take a look at the most common times and days we push
advisories for Red Hat Enterprise Linux 4, 5, and 6 (including
Supplementary) using a heatmap:

The more advisories pushed for a given date and hour, the darker
that section of the graph is. So the most popular times
for pushing advisories are Tuesdays at 10am and 2pm Eastern US time,
Fridays are pretty light for pushes, and there was nothing
during the weekends. The spread of the graph shows that we push advisories when
they are ready, rather than waiting to a fixed day and time, in order to reduce
the risk to users.

All the data used to create this graph is available as part of
our public metrics.
Thanks to Sami Kerola for
the R code from which I based my
graph generation.

Every year since Red Hat Enterprise Linux 4 was released we've
published a risk report where we look at the state of security
of the distribution. We investigate the key vulnerabilities,
metrics on vulnerability counts, and how users could have been
exploited by them. The
Six
Years
of Red Hat Enterprise Linux 4 report (PDF) covering Feb 2005-2011
was published today.

"Red Hat knew about 51.5% of the security vulnerabilities
that we fixed in advance. The
average time between Red Hat knowing about an issue and it being made
public was 23 days (median 10 days).... A default installation of Red
Hat Enterprise Linux 4 AS was vulnerable to 20 critical security
issues over the first six years. "

The data we publish is interesting to get a feel for the risk of running
Enterprise Linux, but isn't really useful for comparisons with other
distributions, or operating systems. One important difference is that it is Red
Hat policy to count vulnerabilities and allocate CVE names to all issues that
we fix, including ones that are found internally. This is not true for many
other vendors including folks like
Microsoft
and
Adobe
who do not count or disclose issues they fix which were found internally.

A few weeks ago the 2011 update to
the CWE/SANS Top 25 Most Dangerous
Software Errors was published. As part of our contribution to this
update we analysed the most severe vulnerabilities that affected Red Hat
since the last update and mapped each one to the appropriate Common
Weakness Enumeration (CWE) type.

The table below lists all vulnerabilities which have a CVSS score of 7
or more ('high'), that we fixed in any product during calendar year 2010.

Red Hat Enterprise Linux 5.7 was released last week (July 2011), six months
since the release of 5.6 in January 2011. So let's use this opportunity to take
a quick look back over the vulnerabilities and security updates made in that
time, specifically for Red Hat Enterprise Linux 5 Server.

Errata count

The chart below illustrates the total number of security updates issued for Red
Hat Enterprise Linux 5 Server if you had installed 5.6, up to and including the
5.7 release, broken down by severity. It's split into two columns, one for
the packages you'd get if you did a default install, and the other if you
installed every single package (which is unlikely as it would involve quite a bit of
manual effort to select every one). For a given installation, the number of
package updates and vulnerabilities that affected you will depend on exactly
what packages you have installed or removed.

So, for a default install, from release of 5.6 up to and including
5.7, we shipped 27 advisories to address 109 vulnerabilities. 3
advisories were rated critical, 12 were important, and the remaining
12 were moderate and low.

Or, for all packages, from release of 5.6 to and including 5.7, we
shipped 58 advisories to address 172 vulnerabilities. 4 advisories
were rated critical, 20 were important, and the remaining 34 were
moderate and low.

Critical vulnerabilities

The 4 critical advisories addressed 34 critical vulnerabilities across just 2 different packages:

An update to OpenJDK 6 Java Runtime Environment,
(June 2011)
where a web site hosting a malicious Java applet could potentially run
arbitrary code as the user.

Three updates to Firefox (March 2011, April 2011, June 2011)
where a malicious web site could potentially run arbitrary code as the user
running Firefox.

Updates to correct all of the 34 critical vulnerabilities were
available via Red Hat Network either the same day or the next
calendar day after the issues were public.

Overall, for Red Hat Enterprise Linux 5 since release until 5.7, 97%
of critical vulnerabilities have had an update available to address
them available from the Red Hat Network either the same day or the
next calendar day after the issue was public.

Other significant vulnerabilities

Although not in the definition of critical severity, also of interest during
this period were a couple of flaws that were easily exploitable:

A flaw in dhcp,
CVE-2011-0997,
fixed by
RHSA-2011:0428, where a malicious DHCP
server could send a response that could lead to arbitrary code execution on connecting clients.

Previous update releases

To compare these statistics with previous update releases we need
to take into account that the time between each update release is different.
So looking at a default installation and calculating the number of
advisories per month gives the following chart:

This data is interesting to get a feel for the risk of running Enterprise
Linux 5 Server, but isn't really useful for comparisons with other major
versions, distributions, or operating systems -- for example, a default install
of Red Hat Enterprise Linux 4AS did not include Firefox, but 5 Server does. You
can use our public
security measurement data and tools, and run your own custom metrics for any
given Red Hat product, package set, timescales, and severity range of interest.